Microgranular acute promyelocytic leukemia presenting with leukopenia and an unusual immunophenotype

MPO Expression of Background Neutrophils in MPO Negative Acute Promyelocytic Leukemia, An Easy Clue to Corroborate a Challenging Diagnosis: A Case Report and Review of Literature

Acute promyelocytic leukemia (APL) is characterized by the pathogenic driver fusion transcript PML-RARA resulting from the t(15;17) translocation. Early recognition of APL with prompt ATRA induction has a decisive impact on the early death rate. The preliminary diagnosis of APL relies heavily on cytomorphology and flow cytometry. In APL with variant morphology, such as the microgranular variant, immunophenotype, especially the bright MPO positivity is the basis of diagnosis. Till date, only five cases of APL with reduced/absent MPO have been described in literature. The identification of MPO deficiency based on genetic testing would involve at the least a MPO gene scanning with NGS, followed by microarray to identify somatic uniparental disomy in heterozygotes. This testing is not only redundant given the scant clinical implications of heterozygous MPO deficiency but also time consuming. An easy way to identify background MPO deficiency confounding the immunophenotype of a myeloid neoplasm is the MPO expression in background neutrophils gated on the initial flow cytometry. A dim MPO in the background neutrophils, in the morphological setting of APL, can identify underlying MPO deficiency, clarifying the immunophenotypic ambiguity and thus establishing an unequivocal diagnosis as seen in the current case.

Favorable outcome of PML-RARα short isoform and FLT3-ITD mutation in a patient with several adverse prognostic markers: A case report

Key Clinical Message

Complete molecular remission in a "variant APL" patient with short isoform of PML-RARα and FLT3-ITD mutation was achieved in response to ATRA and ATO plus IDA instead of standard treatment protocol. The use of FLT3 inhibitor in APL induction management is implicated to prevent differentiation syndrome and coagulopathy experienced in in patients with FLT3-ITD.

Abstract

FLT3-ITD mutations are the most common activating mutations in FLT3 gene, occurring in about 12 to 38% of acute promyelocytic leukemia cases, and are mainly associated with high white blood cell counts and poor clinical outcomes. Here, we present a case of APL variant with adverse prognostic features who showed short isoform [bcr3] of PML-RARα and FLT3-ITD mutation at diagnosis. The patient received all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) plus idarubicin (IDA) instead of standard treatment protocol, and achieved a complete morphological, cytogenetic and molecular response. However, the patient experienced differentiation syndrome, and coagulopathy that was subsequently resolved by continuous oxygen therapy, dexamethasone, and enoxaparin. The use of FLT3 inhibitor in APL induction management is implicated to prevent differentiation syndrome and coagulopathy in patients with FLT3-ITD mutation.

What Is Different in Acute Hematologic Malignancy-Associated ARDS? An Overview of the Literature

Background and Objectives: Acute hematologic malignancies are a group of heterogeneous blood diseases with a high mortality rate, mostly due to acute respiratory failure (ARF). Acute respiratory distress syndrome (ARDS) is one form of ARF which represents a challenging clinical condition. The paper aims to review current knowledge regarding the variable pathogenic mechanisms, as well as therapeutic options for ARDS in acute hematologic malignancy patients. Data collection: We provide an overview of ARDS in patients with acute hematologic malignancy, from an etiologic perspective. We searched databases such as PubMed or Google Scholar, including articles published until June 2022, using the following keywords: ARDS in hematologic malignancy, pneumonia in hematologic malignancy, drug-induced ARDS, leukostasis, pulmonary leukemic infiltration, pulmonary lysis syndrome, engraftment syndrome, diffuse alveolar hemorrhage, TRALI in hematologic malignancy, hematopoietic stem cell transplant ARDS, radiation pneumonitis. We included relevant research articles, case reports, and reviews published in the last 18 years. Results: The main causes of ARDS in acute hematologic malignancy are: pneumonia-associated ARDS, leukostasis, leukemic infiltration of the lung, pulmonary lysis syndrome, drug-induced ARDS, radiotherapy-induced ARDS, diffuse alveolar hemorrhage, peri-engraftment respiratory distress syndrome, hematopoietic stem cell transplantation-related ARDS, transfusion-related acute lung injury. Conclusions: The short-term prognosis of ARDS in acute hematologic malignancy relies on prompt diagnosis and treatment. Due to its etiological heterogeneity, precision-based strategies should be used to improve overall survival. Future studies should focus on identifying the relevance of such etiologic-based diagnostic strategies in ARDS secondary to acute hematologic malignancy.

Recent Advances in the Management of Pediatric Acute Myeloid Leukemia-Report of the Hungarian Pediatric Oncology-Hematology Group

Simple Summary

The outcome of pediatric AML improved considerably worldwide during the past few decades. Hereby, we summarize the therapeutic results of pediatric AML patients registered between 2012 and 2019 in Hungary. As compared to our previous results, improvement was registered in event-free (EFS) and overall (OS) survival, which can be attributed to the application of contemporary diagnostic and therapeutic guidelines, advanced supportation, and higher efficacy of hematopoietic stem cell transplantation. Between 2016 and 2019, a statistically significant increment of 2-year EFS was confirmed over the period between 2012 and 2015. The most prominent progress was observed in acute promyelocytic leukemia (APL). Multidimensional flow cytometry made possible the prompt introduction of ATRA in two cases with M3v, who also represent the first pediatric APL patients in Hungary to be treated with arsenic-trioxide. Besides joining multinational pediatric AML treatment groups, our future aims include the introduction of centralized treatment centers and diagnostic facilities.

Abstract

Outcome measures of pediatric acute myeloid leukemia (AML) improved considerably between 1990 and 2011 in Hungary. Since 2012, efforts of the Hungarian Pediatric Oncology-Hematology Group (HPOG) included the reduction in the number of treatment centers, contemporary diagnostic procedures, vigorous supportation, enhanced access to hematopoietic stem cell transplantation (HSCT), and to targeted therapies. The major aim of our study was to evaluate AML treatment results of HPOG between 2012 and 2019 with 92 new patients registered (52 males, 40 females, mean age 7.28 years). Two periods were distinguished: 2012–2015 and 2016–2019 (55 and 37 patients, respectively). During these periods, 2 y OS increased from 63.6% to 71.4% (p = 0.057), and the 2 y EFS increased significantly from 56.4% to 68.9% (p = 0.02). HSCT was performed in 37 patients (5 patients received a second HSCT). We demonstrate advances in the diagnosis and treatment of acute promyelocytic leukemia (APL) in two cases. Early diagnosis and follow-up were achieved by multidimensional flow cytometry and advanced molecular methods. Both patients were successfully treated with all-trans retinoic acid and arsenic-trioxide, in addition to chemotherapy. In order to meet international standards of pediatric AML management, HPOG will further centralize treatment centers and diagnostic facilities and join efforts with international study groups.